FRF: 8216975 Using ForceNUMA does not disable adaptive sizing with parallel gc
ivan.walulya at oracle.com
Thu Feb 20 08:04:45 UTC 2020
Here is the revised webrev: http://cr.openjdk.java.net/~iwalulya/8216975/01/ <http://cr.openjdk.java.net/~iwalulya/8216975/01/>
> On 19 Feb 2020, at 16:30, Kim Barrett <kim.barrett at oracle.com> wrote:
>> On Feb 19, 2020, at 10:23 AM, Kim Barrett <kim.barrett at oracle.com> wrote:
>>> On Feb 19, 2020, at 3:35 AM, Ivan Walulya <ivan.walulya at oracle.com> wrote:
>>> Hi all,
>>> Please review a minor modification to disable adaptive sizing when ForceNuma is used with ParallelGC and UseLargePages on Linux OS.
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8216975
>>> <https://bugs.openjdk.java.net/browse/JDK-8216975>Webrev: http://cr.openjdk.java.net/~iwalulya/8216975/00/ <http://cr.openjdk.java.net/~iwalulya/8216975/00/>
>>> Testing: Tier 1 - 3
>> Setting UseNUMA true when Linux::libnuma_init returns false seems
>> unlikely to work. The description of ForceNUMA is
>> Force NUMA optimizations on single-node/UMA systems
>> which suggests how it's presently being used in numa_init is wrong. I
>> think the current use should be removed and this conditional clause
>> 5129 // If there's only one node (they start from 0) or if the process
>> 5130 // is bound explicitly to a single node using membind, disable NUMA.
>> 5131 UseNUMA = false;
>> should instead use
>> UseNUMA = ForceNUMA
> The Solaris use of ForceNUMA looks like it has a similar problem.
> On Windows, UseNUMA seems to get forced off unless ForceNUMA, because
> NUMA support isn’t complete there. Which is an entirely different meaning for
> ForceNUMA from its description.
> That covers all the uses of ForceNUMA.
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